I specialize in Shopify development and am well-equipped to add custom discount code functionality to your Order Printer app. With expertise in coding and customizing Shopify apps, I can seamlessly integrate the code with the payment system, ensuring swift completion to meet your urgent deadlines. I'm experienced in payment system integration within Shopify and can swiftly implement the custom discount code. Let's work together to enhance your Order Printer app with this added functionality, ensuring a quick and efficient solution.